The present invention relates to a gear-motor closing-part-drive for a motor vehicle. The present invention also relates to an associated method for manufacturing the gear-motor closing-part-drive.
In this type of drive, an electric motor displaces a closing part between a closed end position and an open end position via a gearing mechanism. Therein, the closing part is, for example, a motor vehicle window or motor vehicle sun roof. Preferably, the electric motor is a commutator motor and the gearing mechanism is a worm gearing mechanism.
To absorb undesirable shock loads when the end position is reached or when an obstacle is encountered that would affect the electric motor and, in particular, the gear unit, it is known in the art to provide absorption elements between a drive-side gear wheel and a driven-side carrier.
European Patent EP 0 261 525 B1 teaches stop absorption means for a gear-motor-actuating drive, in which an elastic absorption disk is axially placed between the gear wheel and the carrier. The gear wheel or carrier has axially protruding carrier segments, which engage with corresponding carrier openings of the absorber disk in order to facilitate a mutual slip-free rotational drive in a normal operation mode, or in order to facilitate a mutual relative movement between the gear wheel and the carrier when a stop occurs.
European Patent EP 0 549 817 B1 teaches a stop absorption means for a gear-motor actuating drive, wherein the outer gear rim of the gear wheel is connected with the carrier as an integral injection molded part. This connection is realized via spring-type spokes that are, to a certain extent, tangentially elastic for absorption purposes. A separate absorber insert is dispensed with. A driving pinion may also be connected to the carrier by injection molding. Instead of the integral connection between the gear wheel and the carrier through the spring-type spokes, a carrier connection may be provided in such a way that radial carrying segments of one of the two elements reach between tangentially overlapping carrying forks of the other element. The carrying segments and/or the carrying forks may be elastic to provide tangential stop absorption.
German Patent DE 34 03 259 C1 discloses a window regulator gear unit with a backspring arrangement of two rotatably borne gear parts that are coaxially positioned one behind the other. One of the gear parts is provided with at least one axial carrying projection, which is spaced at a distance from the rotary axis and which engages with preferably vibration-absorbing backspring elements provided on the other gear part. Therein, the at least approximately leaf-spring-type backspring elements are integrally formed with the other gear part. The backspring elements are tangentially elastically deformed by the carrying projections positioned therebetween.
It is one object of the present invention to provide a stop absorption arrangement. In spite of using very simple production and assembly technology, this stop absorption arrangement should be largely independent from the normal rotational drive between the gear wheel and the carrier when there is a mutual relative movementxe2x80x94such as the mutual relative movement that would arise due to a sudden impediment of the carrier""s movement while the gear wheel continues to drive.
According to one formulation of the present invention, these and other objects are achieved by providing a gear-motor closing part drive for a motor vehicle, which includes a drive-side gear wheel and a driven-side carrier that is in rotary driving engagement with the drive-side gear wheel. At least one of the gear wheel and the carrier has at least one of integral elastic spring elements and cams. The cams are configured to press against the integral elastic spring elements in order to provide mutual stop absorption when a mutual relative rotational movement between the gear wheel and the carrier occurs. Such mutual relative rotational movement between the gear wheel and the carrier is caused, e.g., when the movement of the carrier is inhibited, while the gear wheel continues to be driven. The spring elements include spring segments, which extend substantially tangentially and which have stopping bevels. The spring segments are arranged such that they are radially elastically deformed by the cams, which slidingly run against the stopping bevels when the mutual rotational relative movement between the gear wheel and the carrier occurs.
According to a preferred embodiment of the invention, the gear wheel and the carrier plate are individually configured and have a rotary driving arrangement and a stop absorption arrangement, respectively. When the gear wheel and the carrier plate are assembled, they form an integral unit.
To simplify production, the gear wheel and the carrier are mutually assembled only as they are mounted in a gearbox or drive-side housing that receives the components. Therein, the gearbox or drive-side housing is provided with an associated shaft. The gear wheel and the carrier are produced as separate, axially superimposed injection molded parts, which are cast in a common injection mold as a production or assembly unit. The gear wheel and the carrier are connected as a production or assembly unit. In particular, connecting brackets or the like are integrally injection molded, which can be pulled off as the parts are assembled from their injection molded position into their mutual operating position.
Advantageously, a mutual play-free fit between the assembled components and a suitable pitch of the respective stopping bevel are provided so as to prevent self-locking between the gear wheel and the carrier after a mutual relative movement has occurred that was caused by the stop.